Vintage Motorcycles Up for Auction

They leak, shake, rattle and spark -- and sell for hundreds of thousands of dollars.

The rarest of rare vintage motorcycles, these decades-old machines are challenging to start and difficult to ride. Yet they are becoming more expensive to purchase despite -- and some say because of -- the down economy.

For years, ultra-obscure bikes such as a 1936 Crocker Twin or a 1907 Curtiss V-8 were collected by a small handful of moneyed gearheads. They had such deep appreciation for the unique designs and temperaments of these machines that they'd willingly use their shins as heat guards, repurpose their feet as brake shoes and consider it a deal to pay tens of thousands of dollars to experience such evolutionary technology.

Now, they're paying six figures. And the price increases are happening even as the market for new motorcycles is tanking.